How to reproduce:
# Create new 2D Core project
# Add any 2D Sprite Sheet somewhere in the Project panel (e.g. Assets folder)
# Select added Sprite Sheet and in Inspector select Sprite Mode : Multiple and click Apply button
# Click Sprite Editor button > Slice > Slice > Apply
# In Hierarchy create new object (2D Object > Sprites > Square)
# Select created object and in top menu open Window > Animation > Animation
# In Animation window click Create (and save animation)
# Drag and Drop three sliced sprites into Animation window
# Try moving added keys left or right
# Check console for errors

Expected results: No error in console. It should be possible to move key frame left/right.
Actual results: Unable to move key frames in Animation window and multiple errors are thrown in the Console window if trying to do so.

{noformat}
InvalidCastException: Specified cast is not valid.
UnityEditorInternal.AnimationWindowKeyframe.ToKeyframe () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditorInternal.AnimationWindowCurve.ToAnimationCurve () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditorInternal.AnimationWindowUtility.CreateRendererForCurve (UnityEditorInternal.AnimationWindowCurve curve) (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditorInternal.AnimationWindowUtility.GetCurveWrapper (UnityEditorInternal.AnimationWindowCurve curve, UnityEngine.AnimationClip clip) (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditorInternal.AnimationWindowState.get_activeCurveWrappers () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditor.AnimEditor.UpdateCurveEditorData () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditor.AnimEditor.UpdateSelectedKeysToCurveEditor () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditor.AnimEditor.SaveCurveEditorKeySelection () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
{noformat}

Reproducible on: 2022.2.0a13, 2022.2.0a14, 2022.2.0a18, 2022.2.0a19
Not reproducible on: 2022.2.0a12

Notes: Tested on Win11